Hydraulic inorganic materials, a representative of which is cement, have long been used widely as structural materials and building materials. However, hardened cement bodies are poor in flexural strength, though they have high compressive strength, and many attempts have been made to improve the poor flexural strength. For instance, there have been known a method of using a water-reducing agent to reduce the amount of water added, and a method of adding silica fume or a blast-furnace slag powder so as to make the structure of a hardened cement body denser, thereby seeking an increased strength. Above all, Japanese Patent Publication No. 59-43431 (1984) discloses that, by making the addition amount of water extremely small as compared with the conventional amount and reducing the size of void and the porosity, it is possible to increase the flexural strength of a hardened cement body to at least 7 times the conventional value of 50 to 100 kgf/cm .sup.2.
Besides, as a composite material using a non-hydraulic inorganic material, e.g., calcium carbonate, instead of a hydraulic inorganic material, e.g., cement, there has been known a resin concrete using a urethane resin, polyfunctional acrylic resin or other similar water-insoluble resin as a binder. The resin concrete has been widely used as a floor material, a wall material or a material for table counters.
The conventional resin concrete, using a non-hydraulic inorganic material, often contains a cross-linking type resin as a binder and, as a result, has a short pot life and is limited in kneading and molding times. Accordingly, development of a hardened body excellent in strength (especially, flexural strength) which uses a non-hydraulic inorganic material and is substantially free of such a pot-life problem is now desired.